Programming Games - What Language?

What language are most games made from? What are my options? What are most used? What is Unity?

C++?
C#? (whats the difference between the first 2)
Java?
Any others?

I found this site, and for $100 they ship you around 7 books, and teach you everything about programming:

http://www.gameinstitute.com/

How hard is programming?

Any other info would be great. Any websites you recommend I can learn from? Any info please? Any books? PDF's etc?

Thanks

(I AM NOT ASKING FOR CAREER ADVICE, THIS IS JUST INFORMATION I WANT TO LOOK INTO THE FIELD)

 

Books can be helpful but you have to remember that when it comes to online learning, everything is available for free. You can study MIT courses for free but with no qualification at the end, just the knowledge:
http://ocw.mit.edu/index.htm

I'm sure there would be an online course there that would specifically focus on game programming and the different languages needed for it.

Other free education sites include:
https://www.khanacademy.org/ (better for gaining a general idea on concepts)
https://www.coursera.org/